Transceiver front-end having tx and rx isolation

ABSTRACT

A transceiver front-end comprises a transmitter section a receiver section, and an isolation circuit. The transmitter section includes an oscillation module that generates a radio frequency (RF) oscillation and a power amplifier module that amplifies and modulates the RF oscillation in accordance with outbound modulation information to produce an outbound RF signal. The receiver section includes a low noise amplifier that amplifies an inbound RF signal to produce an amplified inbound RF signal and a down conversion module that converts the amplified inbound RF signal into an encoded inbound signal. The isolation circuit reduces a blocking effect of the outbound RF signal on the receiver section.

This patent application is claiming priority under 35 USC §119 to aprovisionally filed patent application entitled RFID SYSTEM, having aprovisional filing date of Mar. 30, 2007, and a provisional Ser. No. of60/921,221 (attorney docket no. BP 6250); and to a provisionally filedpatent application entitled RFID SYSTEM, having a provisional filingdate of May 31, 2007, and a provisional Ser. No. of 60/932,411 (attorneydocket no. BP 6250.1).

CROSS REFERENCE TO RELATED PATENTS

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STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

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BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

This invention relates generally to communication systems and moreparticularly to RFID systems.

2. Description of Related Art

A radio frequency identification (RFID) system generally includes areader, also known as an interrogator, and a remote tag, also known as atransponder. Each tag stores identification data for use in identifyinga person, article, parcel or other object. RFID systems may use activetags that include an internal power source, such as a battery, and/orpassive tags that do not contain an internal power source, but insteadare remotely powered by the reader.

Communication between the reader and the remote tag is enabled by radiofrequency (RF) signals. In general, to access the identification datastored on an RFID tag, the RFID reader generates a modulated RFinterrogation signal designed to evoke a modulated RF response from atag. The RF response from the tag includes the coded identification datastored in the RFID tag. The RFID reader decodes the coded identificationdata to identify the person, article, parcel or other object associatedwith the RFID tag. For passive tags, the RFID reader also generates anunmodulated, continuous wave (CW) signal to activate and power the tagduring data transfer.

RFID systems typically employ either far-field technology, in which thedistance between the reader and the tag is great compared to thewavelength of the carrier signal, or near-field technology, in which theoperating distance is less than one wavelength of the carrier signal, tofacilitate communication between the RFID reader and RFID tag. Infar-field applications, the RFID reader generates and transmits an RFsignal via an antenna to all tags within range of the antenna. One ormore of the tags that receive the RF signal responds to the reader usinga backscattering technique in which the tags modulate and reflect thereceived RF signal. In near-field applications, the RFID reader and tagcommunicate via mutual inductance between corresponding reader and taginductors.

Currently, RFID readers are formed of separate and discrete componentswhose interfaces are well-defined. For example, an RFID reader mayconsist of a controller or microprocessor implemented on a CMOSintegrated circuit and a radio implemented on one or more separate CMOS,BiCMOS or GaAs integrated circuits that are uniquely designed foroptimal signal processing in a particular technology (e.g., near-fieldor far-field). However, the high cost of such discrete-component RFIDreaders has been a deterrent to wide-spread deployment of RFID systems.In addition, there are a number of different RFID standards, eachdefining a different protocol for enabling communication between thereader and the tag. Discrete RFID reader designs inhibit multi-standardcapabilities in the reader.

Therefore, a need exists for a highly integrated, low-cost RFID reader.In addition, a need exists for an RF front-end that provides isolationbetween the transmitter and receiver.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to apparatus and methods of operationthat are further described in the following Brief Description of theDrawings, the Detailed Description of the Invention, and the claims.Other features and advantages of the present invention will becomeapparent from the following detailed description of the invention madewith reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a schematic block diagram of an embodiment of an RFID systemin accordance with the present invention;

FIG. 2 is a schematic block diagram of an embodiment of an RFID readerin accordance with the present invention;

FIG. 3 is a schematic block diagram of an embodiment of a transceiverfront-end in accordance with the present invention;

FIG. 4 is a schematic block diagram of another embodiment of atransceiver front-end in accordance with the present invention;

FIG. 5 is a schematic block diagram of another embodiment of atransceiver front-end in accordance with the present invention; and

FIG. 6 is a schematic block diagram of another embodiment of atransceiver front-end in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of an RFID (radio frequencyidentification) system that includes a computer/server 12, a pluralityof RFID readers 14-18 and a plurality of RFID tags 20-30. The RFID tags20-30 may each be associated with a particular object for a variety ofpurposes including, but not limited to, tracking inventory, trackingstatus, location determination, assembly progress, et cetera. The RFIDtags may be active devices that include internal power sources orpassive devices that derive power from the RFID readers 14-18.

Each RFID reader 14-18 wirelessly communicates with one or more RFIDtags 20-30 within its coverage area. For example, RFID tags 20 and 22may be within the coverage area of RFID reader 14, RFID tags 24 and 26may be within the coverage area of RFID reader 16, and RFID tags 28 and30 may be within the coverage area of RFID reader 18. In one embodiment,the RF communication scheme between the RFID readers 14-18 and RFID tags20-30 is a backscatter technique whereby the RFID readers 14-18 requestdata from the RFID tags 20-30 via an RF signal, and the RF tags 20-30respond with the requested data by modulating and backscattering the RFsignal provided by the RFID readers 14-18. In another embodiment, the RFcommunication scheme between the RFID readers 14-18 and RFID tags 20-30is an inductance technique whereby the RFID readers 14-18 magneticallycouple to the RFID tags 20-30 via an RF signal to access the data on theRFID tags 20-30. In either embodiment, the RFID tags 20-30 provide therequested data to the RFID readers 14-18 on the same RF carrierfrequency as the RF signal.

In this manner, the RFID readers 14-18 collect data as may be requestedfrom the computer/server 12 from each of the RFID tags 20-30 within itscoverage area. The collected data is then conveyed to computer/server 12via the wired or wireless connection 32 and/or via peer-to-peercommunication 34. In addition, and/or in the alternative, thecomputer/server 12 may provide data to one or more of the RFID tags20-30 via the associated RFID reader 14-18. Such downloaded informationis application dependent and may vary greatly. Upon receiving thedownloaded data, the RFID tag can store the data in a non-volatilememory therein.

As indicated above, the RFID readers 14-18 may optionally communicate ona peer-to-peer basis such that each RFID reader does not need a separatewired or wireless connection 32 to the computer/server 12. For example,RFID reader 14 and RFID reader 16 may communicate on a peer-to-peerbasis utilizing a back scatter technique, a wireless LAN technique,and/or any other wireless communication technique. In this instance,RFID reader 16 may not include a wired or wireless connection 32 tocomputer/server 12. In embodiments in which communications between RFIDreader 16 and computer/server 12 are conveyed through the wired orwireless connection 32, the wired or wireless connection 32 may utilizeany one of a plurality of wired standards (e.g., Ethernet, fire wire, etcetera) and/or wireless communication standards (e.g., IEEE 802.11x,Bluetooth, et cetera).

The RFID system of FIG. 1 may be expanded to include a multitude of RFIDreaders 14-18 distributed throughout a desired location (for example, abuilding, office site, et cetera) where the RFID tags may be associatedwith equipment, inventory, personnel, et cetera. In addition, thecomputer/server 12 may be coupled to another server and/or networkconnection to provide wide area network coverage.

FIG. 2 is a schematic block diagram of an RFID reader 14-18 thatincludes an integrated circuit 56 and may further include a hostinterface module 54. The integrated circuit 56 includes a basebandprocessing module 40, a transmitter section 42, a receiver section 44,and an isolation circuit 46. The baseband processing module 40 may be asingle processing device or a plurality of processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on hard coding of thecircuitry and/or operational instructions. The processing module 40 mayhave an associated memory and/or memory element, which may be a singlememory device, a plurality of memory devices, and/or embedded circuitryof the processing module. Such a memory device may be a read-onlymemory, random access memory, volatile memory, non-volatile memory,static memory, dynamic memory, flash memory, cache memory, and/or anydevice that stores digital information. Note that when the processingmodule 40 implements one or more of its functions via a state machine,analog circuitry, digital circuitry, and/or logic circuitry, the memoryand/or memory element storing the corresponding operational instructionsmay be embedded within, or external to, the circuitry comprising thestate machine, analog circuitry, digital circuitry, and/or logiccircuitry. Further note that, the memory element stores, and theprocessing module executes, hard coded and/or operational instructionscorresponding to at least some of the steps and/or functions illustratedin FIGS. 1-6.

As shown, the baseband processing module 40 may include a protocolprocessing module 48, an encoding module 50, a digital-to-analogconverter (DAC) 52, a digitization module 54, a predecoding module 56and a decoding module 58. The transmitter section 42 includes a poweramplifier module 62 and an oscillator. The receiver section 44 includesa low noise amplifier (LNA) module 64 and a down conversion module 66.Note that the host interface module 54 may include a communicationinterface to a host device, such as a USB dongle, compact flash orPCMCIA.

The protocol processing module 48 is coupled to prepare data forencoding in accordance with a particular RFID standardized protocol. Inan embodiment, the protocol processing module 48 is programmed withmultiple RFID standardized protocols to enable the RFID reader 14-18 tocommunicate with RFID tags, regardless of the particular protocolassociated with the tag. The protocol processing module 48 operates toprogram filters and other components of the encoding module 50, decodingmodule 58, and pre-decoding module 56 in accordance with the particularRFID standardized protocol of the tag(s) currently communicating withthe RFID reader 14-18.

In operation, once the particular RFID standardized protocol has beenselected for communication with one or more RFID tags, the protocolprocessing module 48 generates and provides digital data to becommunicated to the RFID tag to the encoding module 50 for encoding intomodulation data. By way of example, but not limitation, the RFIDprotocols may include one or more line encoding schemes, such asManchester encoding, FM0 encoding, FM1 encoding, etc. The DAC 52converts the digital modulation data into analog modulation information70, which is provided to the power amplifier module 62.

The power amplifier module 62, which includes one or more poweramplifiers coupled in series and/or parallel and/or one or more poweramplifier drivers coupled in series and/or parallel, amplifies an RFoscillation 72 based on the modulation information 70 to produce anoutbound RF signal 74. The modulation information 70 may be amplitudemodulation data such as amplitude modulation (AM) or amplitude shiftkeying (ASK), phase modulation data such as phase shift keying (PSK),and/or frequency modulation data such as frequency modulation, minimumshift keying (MSK), or frequency shift keying (FSK). As shown, theoscillation module 60, which may be a phase locked loop, crystaloscillator, etc. generates the RF oscillation 72. Note that the RFoscillation may have a frequency within one of a plurality of frequencybands (e.g., 900 MHz, 2.4 GHz, 5 GHz, 56-63 GHz, etc.).

The LNA module 64, which includes one or more low noise amplifierscoupled in series and/or parallel, receives an inbound RF signal 76,which has a carrier frequency substantially the same as, or similar to(e.g., within a few percent), the carrier frequency of the outbound RFsignal 74. The LNA module 64 amplifies the inbound RF signal to producean amplified inbound RF signal. The down conversion module 66 convertsthe amplified inbound RF signal into an encoded inbound baseband signal78. In an embodiment, the down conversion module 66 includes one or moremixers, filters, and/or gain stages to convert the inbound RF signal,which may have an in-phase component and a quadrature component, intothe encoding inbound baseband signal 78.

The digitization module 54, which may be a limiting module or ananalog-to-digital converter, converts the encoding inbound basebandsignal 78 into a digital signal. The predecoding module 56 converts thedigital signal into a biphase encoded signal in accordance with theparticular RFID protocol being utilized. The biphase encoded data isprovided to the decoding module 58, which recaptures data therefrom inaccordance with the particular encoding scheme of the selected RFIDprotocol. The protocol processing module 48 processes the recovered datato identify the object(s) associated with the RFID tag(s) and/orprovides the recovered inbound data 80 to the server and/or computer forfurther processing.

The isolation circuit 46 (embodiments of which will be discussed withreference to FIGS. 3-6) functions to reduce a blocking effect of theoutbound RF signal 74 on the receiver section 44. The blocking effect isessentially the outbound RF signal 74 overshadowing, or blocking, theinbound RF signal 66 at the input of the receiver section 44. Thisovershadowing is caused by the outbound and inbound RF signals 74 and 76having substantially the same, or similar, carrier frequencies and theoutbound RF signal 74 having a power level that is much greater (e.g.,at least 20 dB) than that of the inbound RF signal 76. In an embodiment,the isolation circuit 46 reduces the blocking effect by reducing thepower level of the outbound RF signal 74 received by the receiversection 44.

The transmitter section 42, the isolation circuit 46, and the receiversection 44 may be used as a transceiver front-end in radio devicesbeyond RFID readers. For example, the transceiver front-end may be usedin backscattering transceivers, cellular telephones, radar, highfrequency imaging, etc. Regardless of the particular application, theisolation circuit 46 may be on-chip, off-chip or a combination thereofwith the transmitter section 42 and the receiver section 44.

FIG. 3 is a schematic block diagram of an embodiment of a transceiverfront-end that includes the transmitter section 42, the receiver section44, and the isolation circuit 46. The transmitter section 42 includesthe power amplifier module 62 and the oscillator 60. The receiversection includes the LNA module 64, a blocking module 95, and the downconversion module 66. The blocking module 95 may include a limitingmodule 98 and a subtraction module 97. The isolation circuit 46 includesa first polarized antenna 90 and a second polarized antenna 92. Theisolation circuit 46 may further include antenna interfaces 94 and 96.

In this embodiment, the outbound RF signal 74 is transmitted via thefirst antenna 90, which has a first polarization (e.g., 0°) and theinbound RF signal 76 is received via a second antenna 92, which has asecond polarization (e.g., 90°). The first and second antennas 90 and 92may be monopole or dipole antennas that have a directional radiationpattern. With the antennas 90 and 92 positioned orthogonally to eachother, the radiation patterns of the antennas are at approximately 90°thereby reducing the interference between them (e.g., reducing theblocking signal received by the receiver section 44) by 20 dB or more.

If the isolation module 46 includes antennas interfaces 94 and 96, eachinterface may include an impedance matching circuit, a bandpassfiltering circuit, and/or a transmission line. In this instance, theantenna interfaces 94 provide optimal energy transfer between theantennas 90 and 92 and the corresponding sections 42 and 44.

The blocking module 95 of the receiver section 44 further reduces theblocking component (e.g., the received outbound RF signal) of theinbound RF signal 76 such that the desired signal component of theinbound RF signal 76 is provided to the down conversion module 66. Asconfigured, the limiting module 98 limits the inbound RFID signal toproduce a limited inbound RFID signal that includes a substantiallyattenuated desired signal component and a substantially unattenuatedblocking signal component. In an embodiment, the limiting module 98 alimiter that limits the inbound RF signal 76, which is amplitudemodulated, to a constant envelope signal. The limiting module 98 mayfurther include a scaling module such that the blocking signal componentof the limited inbound signal has a substantially similar magnitude ofthe received blocking signal component.

The subtraction module 97 subtracts the limited inbound RFID signal fromthe amplified inbound RFID signal (i.e., the output of the LNA module64) to produce an amplified and blocked inbound RFID signal. In thisinstance, the amplified and block signal includes a real component ofthe desired signal component with the imaginary component of the desiredsignal component and the blocking signal component substantiallyattenuated.

FIG. 4 is a schematic block diagram of another embodiment of atransceiver front-end that includes the transmitter section 42, thereceiver section 44, and the isolation circuit 46. The transmittersection 42 and the receiver section 44 function as previously discussedwith reference to FIG. 2. Note that the receiver section 44 may furtherinclude the blocking circuit 95 of FIG. 3.

The isolation circuit 46 includes an antenna 100 and a circulator 102.The circulator 102 may a passive device that includes three ports (onefor coupling to the antenna 100, one for coupling to the transmittersection 42, and one for coupling to the receiver section 44). When asignal is present at one of the ports, it is fed to the next port andisolated from the third port. In this instance, when the transmittersection 42 is providing the outbound RF signal 74 via the circulator 102to the antenna 100, the outbound RF signal 74 component to the receiversection 42 is reduced (e.g., 3 dB).

FIG. 5 is a schematic block diagram of another embodiment of atransceiver front-end that includes the transmitter section 42, thereceiver section 44, and the isolation circuit 46. The transmittersection 42 and the receiver section 44 function as previously discussedwith reference to FIG. 3. Alternatively, the receiver section 44 may beconfigured as shown in FIG. 2.

The isolation circuit 46 includes the antenna 100, the circulator 102,and an adjustable antenna module 103. The circulator 102 functions aspreviously discussed with respect to transmitting the outbound RF signal74. When the inbound RF signal 76 is being received, the circulator 102couples the antenna 100 to the adjustable attenuation module 103. Theadjustable attenuation module 103 may include an adjustable low passfilter, an adjustable notch filter, an adjustable bandpass filter, or anadjustable gain stage to reduce the signal strength of the inbound RFsignal 76, which includes the blocking signal component. By reducing thesignal strength of the inbound RF signal 76, the LNA module 64 operatesin a more optimal manner (e.g., more linear) thereby improving thesensitivity of receiver section 44 to detect the desired signalcomponent.

FIG. 6 is a schematic block diagram of another embodiment of atransceiver front-end that includes the transmitter section 42, thereceiver section 44, and the isolation circuit 46. The receiver section44 functions as previously discussed with reference to FIG. 2.Alternatively, the receiver section 44 may be configured as shown inFIG. 3. The isolation circuit 46 includes the antenna 100 and anadjustable antenna module 103, which operates as previously discussed.

In this figure, the power amplifier module 62 includes a power amplifier104 and a transformer 106. The power amplifier 104 amplifies andmodulates the RF oscillation in accordance with the outbound modulationinformation 70 to produce an amplified and modulated RF signal. Thetransformer 106, which may be an on-chip or off-chip transformer balun,electromagnetically produces the outbound RF signal 74 from theamplified and modulated RF signal. In an embodiment, the transformer 106includes a turns ratio of M such that the voltage of the outbound RFsignal 74 is greater than the voltage of the amplified and modulated RFsignal. Note that the power amplifier module 62 of FIGS. 2-5 may beimplemented as shown in FIG. 6.

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “coupled to” and/or “coupling” and/or includes direct couplingbetween items and/or indirect coupling between items via an interveningitem (e.g., an item includes, but is not limited to, a component, anelement, a circuit, and/or a module) where, for indirect coupling, theintervening item does not modify the information of a signal but mayadjust its current level, voltage level, and/or power level. As mayfurther be used herein, inferred coupling (i.e., where one element iscoupled to another element by inference) includes direct and indirectcoupling between two items in the same manner as “coupled to”. As mayeven further be used herein, the term “operable to” indicates that anitem includes one or more of power connections, input(s), output(s),etc., to perform one or more its corresponding functions and may furtherinclude inferred coupling to one or more other items. As may stillfurther be used herein, the term “associated with”, includes directand/or indirect coupling of separate items and/or one item beingembedded within another item. As may be used herein, the term “comparesfavorably”, indicates that a comparison between two or more items,signals, etc., provides a desired relationship. For example, when thedesired relationship is that signal 1 has a greater magnitude thansignal 2, a favorable comparison may be achieved when the magnitude ofsignal 1 is greater than that of signal 2 or when the magnitude ofsignal 2 is less than that of signal 1.

The present invention has also been described above with the aid ofmethod steps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention.

The present invention has been described above with the aid offunctional building blocks illustrating the performance of certainsignificant functions. The boundaries of these functional buildingblocks have been arbitrarily defined for convenience of description.Alternate boundaries could be defined as long as the certain significantfunctions are appropriately performed. Similarly, flow diagram blocksmay also have been arbitrarily defined herein to illustrate certainsignificant functionality. To the extent used, the flow diagram blockboundaries and sequence could have been defined otherwise and stillperform the certain significant functionality. Such alternatedefinitions of both functional building blocks and flow diagram blocksand sequences are thus within the scope and spirit of the claimedinvention. One of average skill in the art will also recognize that thefunctional building blocks, and other illustrative blocks, modules andcomponents herein, can be implemented as illustrated or by discretecomponents, application specific integrated circuits, processorsexecuting appropriate software and the like or any combination thereof.

1. A radio frequency identification (RFID) reader comprises: a basebandprocessing module coupled to: convert outbound data into outboundmodulation information; and convert an encoded inbound signal intoinbound data; a transmitter section that includes: an oscillation modulecoupled to convert a reference oscillation into a radio frequency (RF)oscillation; and a power amplifier module coupled to amplify and tomodulate the RF oscillation in accordance with the outbound modulationinformation to produce an outbound RF signal; a receiver section thatincludes: a low noise amplifier coupled to amplify an inbound RF signalto produce an amplified inbound RF signal; and a down conversion modulecoupled to convert the amplified inbound RF signal into the encodedinbound signal; an isolation circuit coupled to reduce a blocking effectof the outbound RF signal on the receiver section.
 2. The RFID reader ofclaim 1, wherein the isolation circuit comprises: a first antennacoupled to the receiver section, wherein the first antenna has a firstpolarization; and a second antenna coupled to the transmitter section,wherein the second antenna has a second polarization, and wherein thefirst polarization is substantially orthogonal to the secondpolarization.
 3. The RFID reader of claim 2, wherein the isolationcircuit further comprises: a first antenna interface to provide thecoupling between the first antenna and the receiver section; and asecond antenna interface to provide the coupling between the secondantenna and the transmit section, wherein each of the first and secondantenna interfaces provides at least one of: impedance matching,bandpass filtering, and a transmission line.
 4. The RFID reader of claim2, wherein the receiver section further comprises: a blocking modulecoupled to the low noise amplifier, wherein the inbound RF signalincludes a blocking component and a desired signal component, whereinthe blocking component corresponds to reception of the outbound RFsignal by the first antenna, and wherein the blocking modulesubstantially attenuates the blocking component and passes,substantially unattenuated, the desired signal component to produce theamplified inbound RF signal.
 5. The RFID reader of claim 1, wherein theisolation circuit comprises: an antenna; and a circulator coupled to theantenna, the receiver section, and the transmitter section.
 6. The RFIDreader of claim 5, wherein the receiver section further comprises: ablocking module coupled to the low noise amplifier, wherein the inboundRF signal includes a blocking component and a desired signal component,wherein the blocking component corresponds to reception of the outboundRF signal by the first antenna, and wherein the blocking modulesubstantially attenuates the blocking component and passes,substantially unattenuated, the desired signal component to produce theamplified inbound RF signal.
 7. The RFID reader of claim 5, wherein theisolation circuit further comprises: an adjustable attenuation modulecoupled between the circulator and the receiver section, wherein theadjustable attenuation module attenuates the inbound RF signal.
 8. TheRFID reader of claim 1, wherein the isolation circuit comprises: anantenna coupled to the transmit section; and an adjustable attenuationmodule coupled between the antenna and the receiver section, wherein theadjustable attenuation module attenuates the inbound RF signal.
 9. TheRFID reader of claim 1, wherein the power amplifier module comprises: apower amplifier coupled to amplify and to modulate the RF oscillation inaccordance with the outbound modulation information to produce anamplified and modulated RF signal; and a transformer coupled toelectromagnetically produce the outbound RF signal from the amplifiedand modulated RF signal.
 10. A transceiver front-end comprises: atransmitter section that includes: an oscillation module coupled toconvert a reference oscillation into a radio frequency (RF) oscillation;and a power amplifier module coupled to amplify and to modulate the RFoscillation in accordance with outbound modulation information toproduce an outbound RF signal; a receiver section that includes: a lownoise amplifier coupled to amplify an inbound RF signal to produce anamplified inbound RF signal; and a down conversion module coupled toconvert the amplified inbound RF signal into an encoded inbound signal;and an isolation circuit coupled to reduce a blocking effect of theoutbound RF signal on the receiver section.
 11. The transceiverfront-end of claim 10, wherein the isolation circuit comprises: a firstantenna coupled to the receiver section, wherein the first antenna has afirst polarization; and a second antenna coupled to the transmittersection, wherein the second antenna has a second polarization, andwherein the first polarization is substantially orthogonal to the secondpolarization.
 12. The transceiver front-end of claim 11, wherein theisolation circuit further comprises: a first antenna interface toprovide the coupling between the first antenna and the receiver section;and a second antenna interface to provide the coupling between thesecond antenna and the transmit section, wherein each of the first andsecond antenna interfaces provides at least one of: impedance matching,bandpass filtering, and a transmission line.
 13. The transceiverfront-end of claim 12, wherein the receiver section further comprises: ablocking module coupled to the low noise amplifier, wherein the inboundRF signal includes a blocking component and a desired signal component,wherein the blocking component corresponds to reception of the outboundRF signal by the first antenna, and wherein the blocking modulesubstantially attenuates the blocking component and passes,substantially unattenuated, the desired signal component to produce theamplified inbound RF signal.
 14. The transceiver front-end of claim 10,wherein the isolation circuit comprises: an antenna; and a circulatorcoupled to the antenna, the receiver section, and the transmittersection.
 15. The transceiver front-end of claim 14, wherein the receiversection further comprises: a blocking module coupled to the low noiseamplifier, wherein the inbound RF signal includes a blocking componentand a desired signal component, wherein the blocking componentcorresponds to reception of the outbound RF signal by the first antenna,and wherein the blocking module substantially attenuates the blockingcomponent and passes, substantially unattenuated, the desired signalcomponent to produce the amplified inbound RF signal.
 16. Thetransceiver front-end of claim 14, wherein the isolation circuit furthercomprises: an adjustable attenuation module coupled between thecirculator and the receiver section, wherein the adjustable attenuationmodule attenuates the inbound RF signal.
 17. The transceiver front-endof claim 10, wherein the isolation circuit comprises: an antenna coupledto the transmit section; and an adjustable attenuation module coupledbetween the antenna and the receiver section, wherein the adjustableattenuation module attenuates the inbound RF signal.
 18. The transceiverfront-end of claim 10, wherein the power amplifier module comprises: apower amplifier coupled to amplify and to modulate the RF oscillation inaccordance with the outbound modulation information to produce anamplified and modulated RF signal; and a transformer coupled toelectromagnetically produce the outbound RF signal from the amplifiedand modulated RF signal.